A Tale of Four Brothers
by Kida The Freak
Summary: (AU) Gureto Totsuzenhen'i, The Great Mutation. No one knows who it will choose, or why. Few even know of its existence. But when four boys with entirely different personalities come together, the Mutation chooses them. Now, they must learn to hide their secrets of transformation, survive high school, and learn the secret art of ninjitsu in their new form as... turtles? (2k12 verse)
1. A New Friend

(**Whee! My first fanfic! anyway, this is a TMNT AU based on the 2012 series. There will definitely be DonXApril, and I really want there to be Tcest in the form of LeoXRaph, but I'm also debating whether it should be Leorai instead... hmm. Tell me what you think in a review! ^.^ By the way, go listen to Lorde's song "Team". It's what I had playing while I wrote this, and I had it in mind for LeoXRaph)**

**I don't own TMNT in any way, shape or form. I own only the plot.**

* * *

"_Yame_!"

The instructor's shout halted the two sparring teenagers in the middle of their motions, the youth performing with two _shinai_ glancing the thrust of one bamboo sword against the wrist of his opponent. The shout of "stop" summoned the end of the unfinished match, and the students took their respective bows. The sensei stepped forward, beckoning one of the students to speak with him.

"Leonardo," the elder man began with pride when his pupil stopped to stand before him, _shinai_ still in hand. "Your kendo skills have yet to disappoint. However, I am sensing an inner turmoil that is distracting both the mind and the sword, and it would do you well to share your burden and make it lighter."

Leonardo sighed, feeling the sweat covering his face as he pulled off his _men_ and ran his fingers through his black hair. He really didn't want to bother his sensei right now with his petty qualms. The wise instructor had enough on his plate as it was, what with the kendo tournament rapidly approaching.

"I'm fine, sensei Tsuyoi, just… just a little worried about the tournament."

"Ah, yes," Tsuyoi agreed with a brief nod. "If you felt no fear, I must have raised a fool, and you are no fool, Leonardo. You are one of the most studious and respective of my students, and your devotion echoes through your kendo skills. You will be fine, and bring honor to our dojo. This I know."

Leonardo relaxed subtly, not quite totally reassured, but feeling his confidence taking on a stronger root. His face reddened slightly under his sensei's praise, and he ducked his head to smile shyly.

His teacher reached out, patting him firmly on the shoulder. "Go change and rest for the evening. Tiring you out before the competition will do you no good, my student, and you have already done well."

"Thank you, sensei." Leo said, bowing to his teacher, then the dojo as a show of respect before he left through the door to put his equipment away for the day.

The dojo Leo trained in was just an unused part of the neighborhood gym that had become the training room for the local high school's kendo club. As such, the gym had its own locker rooms and showers, for which Leo was grateful. It would be a pain to walk home smelling like the fish the cafeteria served in third grade.

Leo splashed the sink's water onto his face, having finished his shower and dressed in a tank top and shorts. He dabbed at his face with a sweat-soaked towel and studied his appearance in the mirror, reaching for the comb in his gym bag.

He stood about average height for a fifteen year old boy, with neat black hair cut to just the right length. He was obviously of Japanese descent, having close ancestors directly from Japan himself. But his most striking feature was his brilliant blue eyes.

He wasn't quite sure where he got them from, honestly. Neither of his parents had them. He supposed it had something to do with recessive genes, but he didn't think too deeply into the matter. It was what it was, and Leo never obsessed about anything beyond his control.

He gathered up his gym bag and slung it over his shoulder after he tugged on his jacket, pushing open the locker room doors and wandering down the hall to the front desk. It was customary to sign in and out when entering and leaving, and although it wasn't a rule enforced at the gym, Leo made sure to sign his name every time.

It wasn't until he was passing the weight room that the hairs on the back of his neck prickled under what Leonardo could assume was someone's gaze. His steps faltered and he came to a halt before the glass wall of the weight room, looking through the windows with curiosity etched on his face. Instantly, his blue eyes met the radioactive green of a scowling redhead. Like anyone would when they meet the eyes of a stranger, the short-but-muscular redhead turned back to what he was doing; in his case, beating the heck out of the poor punching bag.

Leo didn't know what the other boy's deal was, but that look had sure felt like a challenge.

A challenge he couldn't back down from.

And even though Leo tried to shake that feeling from his mind, it stuck like glue, clinging to his thoughts. He gritted his teeth, tightening the grip on his bag as he turned and left. He didn't look back at the room, but he wanted to.

It wasn't until he was outside that Leo felt like he could breathe better, away from that oddly-inflicted frustration. He sighed, coming down the steps to sit on the  
bench while he waited for the next bus. The congregation of New Yorkers that usually filled the streets to the seams was less than they usually were on a warm fall evening. Only a few other people were walking up and down the sidewalks. Leo leaned back, closing his eyes for just a few moments of rest…

"Hey, dude, you okay?" A cheery voice asked, a finger poking him in the cheek. Leo grunted, squeezing his eyes tighter as he tried to swat away whoever was bothering him.

"Duuuude…" the voice complained. "You've been asleep for an hour! Aren't you like, supposed to catch the bus or something?"

Leo's eyes snapped open at that with a gasp, and he sat up quickly. "What time is it!?" He looked over to the kid kneeling on the bench next to him, a shorter boy with curly blonde hair and a smattering of freckles on his face. He looked like he had the energy of a seven year old, though he couldn't have been much younger than Leo.

The kid grinned cheekily, obviously amused. "Its five thirty, dude, and you just missed the bus five minutes ago."

Leonardo groaned, slouching back into the bench. "Great. Dad's going to kill me…" He covered his face with his hands, feeling ashamed that he let the time slip away from him. Sensei was right. All this worry was wearing him down.

A few moments passed before Leo peeked out from behind his fingers, confused as to why the kid was still sitting next to him, energetically bouncing in a way that was obviously habit. Leo sat up, fixing the boy with a curious look.

"Did you miss the bus too?" he asked.

"Nah, man, I just live over there and saw you still sleeping. Thought you had somewhere important to be."

Leo looked over to where the boy pointed; a cold brick alley without even a fire escape that could have lead to his home.

"You're homeless?"

The boy nodded enthusiastically. "Uh-huh, but I'm not lonely, 'cause then I get to meet people like you. It's boring to just live like 'regular people' do." He said, air-quoting "regular people". Leo couldn't believe how nonchalant he was towards his homeless status, and he looked down at the boy with a feeling of… regret? Pity? Horror?

"How do you keep yourself alive?" He asked, disbelieving.

"Simple!" The boy said, with what Leo was coming to know as one of his signature mischievous smiles. "I just take meals that people throw out, as long as they still smell okay, and I know the best hiding places from the shady guys. I'm good, bro!"

Even as he was speaking, Leo could see how skinny this boy really was. He probably hadn't had a proper meal in a few days. Leo settled on the feeling of pity, and pulled his gym bag from underneath the bench, not answering the curious eyes of the boy. He dug out his wallet, relieved to have found it untouched. At least the boy was not a thief as well as homeless. He fished a twenty from his allowance, handing it to the kid. "Here."

Instantly, the boy put up his hands as if to decline. His blue eyes were wide with surprise. "No way, bro! I just came to talk for you for company, not to take your money! I mean, thanks for offering and all, but-"

"Just take it. Please? It'd make me feel better."

The boy's eyes flicked at the twenty, then to Leo, as though debating whether or not to take it. Reluctantly, he let Leo hand it to him. He looked up at the kendo player with a look of admiration, like a younger brother would to an older brother.

"Thanks dude! If there's ever anything I can do for you in return-"

"Just be sure to spend that on food, and not comics or something, okay? By the way, I never caught your name."

"Michelangelo!" He said, holding out a hand. "But you can call me Mikey!"

Leo smiled a little, accepting the handshake, or a bro-shake, as Mikey later called it. "I'm Leonardo."

"Okay, Leo! You're my new bestest friend!" Mikey said, practically dislocating Leo's shoulder with his shakes. "I won't ever forget your gift of awesomeness, my brave man!"

Leo couldn't help but chuckle at his antics, despite his arm being yanked. He managed to disentangle himself gradually, and had to shake the numb feeling out. "Okay, that's enough. I still need my arm."

Mikey grinned sheepishly, ducking his head. "Sorry, it's just… I haven't had a permanent friend in a long while." His face fell ever-so-slightly, but it still wasn't enough to dim his bright outlook.

Leo smiled gently, putting his hand on Mikey's shoulder. "You're definitely a good kid, Mikey. If anyone wouldn't want to be your friend, I'd be shocked."

Mikey looked up, hopeful and happy. "Thanks bro. And Leo?"

"Hm?"

"You're about to miss the bus again."

"Shoot!" Leo said, jumping to his feet and grabbing his bag again. "I'll see you around the next time I've got kendo practice! See you later Mikey!" He shouted over his shoulder, waving as he jumped up the steps of the bus.

"Bye Leo-dude!"

* * *

The ride back to his apartment was rather uneventful for Leo. He would've fallen asleep again if it weren't for musings about Mikey. He was an interesting kid for sure, not letting anything get him down and depressed. Leo realized with a start that he was already coming to think of the boy like one would feel towards a little brother.

There were few homes in New York. Most people lived in apartments. If you were Leonardo, however, your apartment was pretty close to a mansion. When your dad owns one of the most successful smartphone companies, you tend to A.) Have a lot of money lying around, and B.) Not see your parents very much. Leo unlocked his front door, pushing it open with his unoccupied shoulder. It was no surprise that no one was home to greet him.

Leo sighed and tossed his bag next to the door, kicking it out of the way as he walked over to the fridge. A note was taped to it in perfect cursive, his mother's handwriting, explaining that they wouldn't be back until next week. They had a last-minute business trip. Ignoring the letter, Leo opened the fridge in hopes of finding some of the leftover pizza, which he grabbed and took to the couch. It looks like he'd be ordering pizza the rest of the week. His parents always turned up their noses whenever Leonardo tried to explain that it was his favorite food.

He flicked on the flatscreen TV, flipping channels until he finally settled on a re-run of Space Heroes, his favorite show. He leaned back into the cushions with a sigh, tossing the empty pizza box onto the coffee table. Guess it was just going to be him this week. Normally, that would signify another boring seven days.

But then again, no one is ever really sure when their life will take a complete U-turn.

* * *

Beneath the nighttime city, an aged, but not yet elderly being stirred from its meditation, whiskers twitching in the dim light that filtered through a grate above. Red-brown eyes snapped open, and the sound of a sharp breath broke the silence.

"Gureto Totsuzenhen'i…" It murmured. "It is rousing."


	2. United as One

**(Whee! Another Chapter! XD Anyway, I'm probably going Leo/Raph with this one, just as a heads up!)**

* * *

Leo groaned, rolling over to try and find his missing sheets that always seem to find a way to disappear sometime in the middle of the night.

All he accomplished was getting a bump on the head as he slipped off the couch.

Groggily, Leo sat up, his normally perfect hair sticking up on all sides. He began feeling weird last night before he drifted off on the couch-which is in itself something Leonardo would_ never_ do-and he still felt that odd sensation this morning. As if to add insult to injury, the clock on the wall glared at him with the time of one-seventeen.

In the afternoon.

For a while, Leo didn't understand why it said it was so late, and he didn't move for a bit, sleepily gaping up at the wall clock. When the time finally dawned on him, he shoved down his panic. The power must have gone out sometime last night, he tried to rationalize, pushing himself up with the coffee table. He winced as a hand was covered in leftover pizza grease. He grabbed the remote and flicked off the TV with his clean hand, and all but stumbled into the kitchen. Maybe a power outage screwed with the time.

It was right after he washed the pizza sauce off that he remembered that the clock ran on batteries. Leo groaned and hit his head on the fridge, emphasizing the bad day this was turning into. He'd have to call in sick; there was no way he'd go to school with only an hour of class left, and this way his parents wouldn't kill him if they found out he missed a day. But one thing was for sure. Leo would make sure to never miss another day of school again.

His dad would probably already be stern with him when he got home. Mr. West was the kind of father with great expectations, which is why Leo is taking numerous Honors classes. He wasn't a bad father, not at all. He just asked much of his family. _And_, Leo thought, unbidden, _he isn't around as much as I'd like him to be…_

Leo did his best to push his musings about his family aside, opting instead to shower. It may be too late for him to go to school, but he could still find something to do in New York. Leo went into his personal bathroom, turning on the water in his shower to a temperature that was not quite hot, but not lukewarm either. Leo shut his door deciding that his shower would not take more than ten minutes.

After his shower, Leo threw on a blue sleeveless hoodie and jeans, grabbing his backpack as an afterthought. Maybe later he would return that book he borrowed from sensei Tsuyoi on Japanese history. He locked the apartment up, a force of habit, before he took the elevator down.

The streets were definitely busier today, and Leo had to jostle among the crowd, pushing past people and wincing when elbows struck his side or when people stepped on his toes. Briefly, he wished he could just travel by air, or rooftop, even, to avoid the masses that seemed just so… monotonous.

It made Leo feel small, sometimes. Insignificant. He was just another face in this crowd, moving along with the other nameless people in one big group. He didn't stand out any more than the person next to him. Or behind him. He was just… average.

He sounded harsh on himself, but it was the truth. No one around him saw anything different in the people nearby. But then again, nobody was every truly average, he supposed. He thought of Mikey, the kid from the other day. Anyone else would write him off as a poor child, and they'd probably assume he was some thief, desperate to survive. Heck, even Leo had wondered if he would try to steal from him. And then Leo got to know the kid, and he was pretty nice. He even tried to decline when Leo offered him money to keep himself alive.

He was a neat kid, Leo mused as he bumped into some African-American guy in a pink sweater. He definitely wouldn't mind grabbing a pizza with him sometime, but he couldn't say what would happen if his dad found out he was hanging out with a homeless boy.

_Maybe I'll visit Mikey again_, Leo decided, darting through the crosswalk to the other side of the street_. I feel like some company_. If the kid wasn't there today, He'd just walk the extra block to drop off the book.

As Leo got closer to where he met Mikey yesterday, the sounds of yelling and a cry of "ya little freak" reached his ears. Leo furrowed his brow, picking up his pace. By the time he rounded the corner, he had broken into a sprint, and now he skidded to a halt. Mikey was in the center of a ring of boys who definitely didn't look like good news. Every time Mikey got close to the edge of the ring, one of the boys would shove him forward, back towards who Leo assumed to be their crew leader. His eyes went wide with shock when he recognized the redhead from the gym, and Leo ran over, jostling the loop of boys out of the way to get to Mikey. The redheaded teen had him by his shirt collar, hauling the blonde up to glare at him.

"Listen, you, jus' gimme that back, an' I promise ya won't get pounded into th' dirt. Sound good?" the leader threatened, snarling.

Mikey just swallowed and tried to squirm out of his grasp, to no avail. "I swear I didn't take it!" He cried, kicking his feet pathetically. "Just-just put me down! Please!? I-I'll make it up to you! I swear!"

"Ya can make it up ta me now! You street trash, ya could'a escaped a beatdown, but noooo…" The teen pulled back a fist, ready to strike.

"Stop!"

The redhead turned to see Leo, who had just pushed passed the others. Mutterings of "This ain't your business," and "stay out of it, pretty boy," were hissed from the troop, who didn't dare mess with their leader's 'justice'. Mikey whimpered pitifully, cracking open an eyelid to look at Leo hopefully. The desperation in his eyes made Leo's jaw clench, and his hands curled into fists.

"Put him down."

The strongly built redhead turned, narrowing his eyes when they met Leo's frame. "This doesn't concern you. 'Sides, this trash-for-brains stole something of mine!"

Leo's gaze flicked briefly to Mikey, look plainly asking if what the redhead said was true. Mikey shook his head, although a little too fast. Leo figured it was because he was still dangling above the ground. Leo glared at the other teen, harder.

"Put. Him. Down."

The wind seemed to speed up with Leo's determined command, whipping his black hair violently. Growling, the leader tossed Mikey to the side none-too-gently, his posse keeping the homeless boy in the circle. He stalked closer to Leo, hands balled into fists. "As you command, oh fearless leader," He mocked. "I simply must _tremble_ in your presence! Listen close, 'cause I don't wanna repeat myself," He jabbed Leo in the chest, roughly, and scowled when he hardly moved. "You don't tell me what to do. Got it?"

The street had all but emptied now, the few people still around casting wary glances at the assembled group before turning down different streets. The sky, as though sensing the imminent conflict, was darkening to a stormy purple, and the wind picked up to blow the trash along the sidewalk like tumbleweed before a showdown.

A few of the redhead's crew were shifting nervously, casting worried glances at the howling sky. One broke the circle, running off to escape what would soon be some nasty weather. _Odd_, Leo thought. _The weather was supposed to be fine today_…

"Raph!" one of the boys said from behind the leader. "Looks like we're gonna get a storm soon. C'mon, let's head back. They ain't worth it!"

He turned and snarled at the one who spoke up. "You buncha' wusses can run back home to mommy, I ain't leaving until the kid pays for stealing!" He cracked his knuckles, and Leo wondered how this boy, shorter than Leo and just barely taller than Mikey, could seem so determinedly threatening. He braced himself, ready for a fight. In addition to being a kendo player, he was pretty skilled at martial arts, too. And now was the time where that kind of skill came in handy.

The leader swung, not caring that the few boys left were edging away from his chance of revenge. Leo saw his fist coming towards his face, and ducked beneath it, grabbing the redhead's wrist and using his momentum to throw him onto his back with an "oomph" sound. Leo stepped back as he got to his feet, fixing him with a look that screamed Leo's funeral.

"Ya done it now, pretty boy!" he snarled baring his teeth as he charged him.

Vaguely, Leo remembered Mikey standing behind him and he did his best to move away from where he assumed the kid was. He sidestepped the rampaging ball of anger, looking over his shoulder to see that Mikey was being pulled out of range by a brown haired boy in glasses. From the looks of it, Mikey was insisting he stay, and Leo turned attention back to the fight, dodging another blow.

"Get back and fight!" The redhead roared against the whipping wind, squinting to shield his eyes. Even Leo was beginning to feel the wind choking him. He backed up to where Mikey and the other boy were, raising his arms to protect his face. The rumbling sound of thunder met their ears, and a flash of blue-green electricity descended upon the city.

"Uh, now's probably not the time to mention this, but isn't lightning supposed to strike _before_ the thunder!?" The brunette shouted, holding onto his glasses.

"We need to get out of this storm!" Leo called, looking around for a shelter. It was difficult to see three feet in front of him, and if they stayed out any longer…

"Way ahead of you, dude!" Mikey's voice called, and Leo turned to see him pointing at an underground subway station that had been closed down a few weeks ago. Already, he and the other boy were fighting against the wind, grabbing onto the railing as they made their way down the steps. Perfect! Leo took a step forward, only to stop and look back at where the redhead was struggling to get to him. Leo sighed. Stupid hero's complex.

In an instant, Leo was at the gang leader's side, hauling him to his feet.

"What're ya…?" The redhead asked, fixing Leo with a curious look in his green eyes.

Leo choked back the wind, screaming over the howling storm and a slap of thunder. "When I give the word, step forward, okay?"

"You ain't the boss of me!" The other boy hissed. Nevertheless, he stepped in the direction of the subway when Leo shouted "Go!" They marched forward like this repeatedly, the combined effort of their footsteps at the same time pushing them forward. It seemed like it took an hour, (although in reality it couldn't have been more than a few minutes) but they finally reached the bottom of the steps, diving into the run-down space of the old station.

Leo moved behind the stairs to avoid the wind that was still lashing into the underground space, ignoring the redhead who was following behind him. It seemed like all his earlier fight left his body, and Leo figured it was from having to fight against that storm. Even he was tired, and he could perform multiple sets of katas with little effort.

Mikey and the brunette were slumped in the corner behind the wall, sharing a jacket to guard against the chill. Instantly, Mikey's blue eyes lit up when he saw Leo, jumping up and practically sending the other boy sprawling on the floor. He threw his arms around Leo's middle, hugging him tight.

"Leo! My big bro's okay!" Leo laughed a little, trying to pry the blonde's fingers off of him.

"Okay, okay, you can let go now!" Mikey let go with a sheepish smile, dancing back a few steps as the brunette stepped up next to him. Leo glanced over at him

"Thanks for getting Mikey out of there," with a smile. "I'm Leo."

"My name's Donatello, but everybody calls me Donnie," he said, nodding. "And we got lucky. I've never seen a storm as... unusual that before! What kind of idiots were you guys, to start a fight in the middle of something like that?"

Leo winced a little, figuring that it was one of the dumber moments in his life. "Not smart, was it?"

"Nope."

Leo laughed nervously, rubbing the back of his neck. His eyes widened when he saw the redhead jump into the lowered area for the subway over Donnie's shoulder.

"Hey, wait! I don't think we're supposed to-"

"Relax, fearless!" The redhead called, waving him off without looking back. "This station's been closed fer a while! No way they kept the power on, so why not explore a bit? We'll be stuck here a while, anyway!"

Leo looked at his retreating back with a look that could only be described as irritation. "You don't know what's down there!"

"All the more reason to explore!"

Leo sighed, turning to Donnie and Mikey. "Should we go after him?"

Donnie nodded. "Oh yeah, definitely. Before the hot head gets himself killed."

They stepped down onto the rails after him, carefully avoiding the bar that would normally be active. Trash littered the dimly lit space, and graffiti coated the walls of the tunnel, saying things like "Jones is everywhere" or "Beware the dogs". One in particular caught Leo's eye, a crude drawing of a turtle with a hastily-scribbled signature of-

"'Mikey'…"

The blonde froze and turned, a sheepishly innocent expression on his face. "Yeessss, Leo?"

"You know that can be considered vandalism, right?" he said, pointing at the sketch.

"Aww, come on Leo, it's just chalk! Oof!"

He ran into Donnie, who had stopped to look around. "Do you guys… do you feel that?"

Leo paused, senses alert for whatever Donnie was trying to describe. He could hear a faint dripping sound, which seemed to come from beneath him. Probably a sewer pipe. Other than that he felt-

Wait… he could feel something. Sort of like rocks being scraped up his back, but… less painful and more tingly."Yeah, I feel it."

"Whoa…" Mikey exclaimed. "That is one wicked feeling, man! It's like floating on feather pillows!" He made a face that made Leo nearly laugh.

"What?" Donnie said, casting a confused glance over his shoulder. "No, not that feeling, the one that feels like a prickling along your skin. Wait, are you guys telling me you're feeling something different?"

"No, duh _Donnie_." The hot head in the lead said sarcastically, scowling at the others. "I don't think pillows and prickling sensations are similar."

Donatello narrowed his brown eyes at him, as though looking at him through a microscope. "You're feeling something too, aren't you?"

He scoffed, looking irritated. "No, I think you guys are just scared. Now come on, let's keep-"

In a split second, a rumbling filled the tunnel, and parts of the ground fell away under their feet. Four bodies tumbled into the shadows beneath them, a cry of "Earthquake!" filling the air as they slipped into the unknown.

Leo just hoped this wasn't the end.

* * *

The aged being paced in its darkened room, a sharp twinge having pulled it from meditation. That twinge signified the moment the Great Mutation's chosen ones were united. Now, it felt a tugging in the pit of his stomach, a sign that the Mutation has accepted them. It knew what to do now. It grabbed a paper lantern from a hook, slipping into the tunnels to follow where the Mutation had summoned it.

It could only hope that whoever was chosen had survived.

* * *

**(And there you have chapter two folks! XD I think we all know who the redhead and the aged being is, and I left another character's appearance in there, if you can find it! X3)**


	3. Transformed as Four

(**Whee! I haven't abandoned this yet! I am so proud of myself! I even got it done with my wisdom teeth having been removed yesterday! ^.^ However, I think I went a little too dramatic with this chapter... oops. Let me know if there is any way at all for me to edit or improve on this or the earlier chapters, m'kay? And for anyone who has missed my other author's notes...**

**WARNING! THIS STORY WILL LIKELY CONTAIN TCEST IN THE FORM OF LEO/RAPH!**** I completely understand if that is not your cup of tea and you start unfollowing immediately! However, I assure you that in this AU they are not blood-related, and any romance I add in is purely emotional fluff. No smut or highly-sexualized content will be added.**

**Besides, the romantic parts aren't gonna show up until about the middle of the story.**

**No flames for the announcement, please!**

**Guest- Glad you know Mikey enough to know he's definitely stolen something! ;) I put that little tidbit in this chapter, like I had been planning on)**

**-Enjoy! **

**-Kida The Freak**

* * *

Leo hauled himself out of the water and onto a concrete bank, gasping for air. He was trembling, pushed up on his hands and knees as he coughed up the liquid he inhaled.

_Breathe, Leo breathe_, he commanded himself. _Just like sensei Tsuyoi taught you… Great, six fingers. I'm hallucinating_.

He squinted down at his hands, willing himself to see clearly. When he still couldn't see more than three fingers on each hand, he sighed, flopping down to rest on his stomach. The feeling he had felt in the tunnel had evaporated now, replaced by a skull-splitting headache. His body felt numb and cold and he just wanted to curl up and take a nap…

He snapped his eyes open at the thought, sitting up quickly. Taking a nap after nearly drowning sounded like a free pass to death, and Leo stood on shaky legs. He needed to find the others, get out of here and get help.

How did he get down here anyways? He remembered an earthquake and a crack splitting open between the rails, but a cursory study of the ceiling showed no scars or flaws. Just the dull, curved roof of what seemed to be a large sewer tunnel._ Actually_, Leo thought with a slight smile_. It's more like an underground lake_. He must have drifted downstream from where he fell, and Leo was just grateful the water looked clear, if a little… glowy.

Eyeing the sidewalk-like edges of the tunnel, Leo decided that they were his best bet out of this place. He stretched his legs and then his arms, trying to get feeling back into his limbs. However, when he tried flexing an arm over his back, something blocked the complete movement of his shoulder blade. Leo frowned, rolling his shoulder again slowly. Once more, he felt a slight resistance of something firm against his arm.

Leo twisted, trying to see what he kept bumping into. He spun in circles, chasing whatever it was like a dog chasing his tail and a cold feeling of dread settled in his chest. No matter what, it was stuck on his back, and all the feeling he managed to get was telling him it's staying for good.

Leo stopped trying to grab at it, focusing on breathing evenly. So far, it was proving to be a very difficult task to keep from panicking. He just had to know what it was. Carefully, Leo reached behind himself, ignoring that faint tug on his shoulder. He brushed his fingertips along his back, inspecting the object.

It was a curved shape, but not too bulky as to constrict movement, and it felt vaguely like there was a ridge surrounding it. The inner surface felt much like a puzzle of hexagons, each connecting to form the convex material. It felt firm and solid, too. Leo bit his tongue, a memory of one of his teacher's class pets surfacing in his mind. It felt like a-

The sound of violent splashing and a sputtering sound snapped Leo out of his confusion, and he jerked around to look at the water's edge. A hand had thrust from the water, grasping at the concrete ledge. A head followed, appearing as a faint smudge in the weak lighting.

Leo rushed over, grabbing the wrist to haul the person from the water. He was sure it had to be one of the others; Leo doubted that there would be anyone else swimming down here, let alone voluntarily. Another hand snaked from the water, taking hold of his free hand, and Leo pulled him onto the concrete with a grunt of effort. He sat on the ground with an exhausted sigh a few feet away from his rescued companion. Whichever one of the boys he pulled out needed to lose some weight!

"You okay?" Leo asked when he caught his breath.

The other boy hissed, pulling into a sitting position.

"Think so… Just a little- What the heck!?"

The other boy, whose voice sounded like the redhead's, scrambled backwards into a shaft of pale light, pointing a shaky finger at Leo. Leo had jumped back in surprise, turning around quickly, trying to see what he was pointing at. A look of startled confusion crossed his face, and he looked back at the hothead with a look of worry.

He wasn't pointing at something behind Leo.

He was pointing _at_ Leo.

Leo swallowed, slowly raising his shaking hands to inspect them. Slowly, he moved them into a small beam of dusty light. What he saw nearly made him choke.

His hands were green, and still had only three fingers. He reached up to touch his face, shock freezing his expression. He had no nose or ears, but he could still hear and smell. Looking over his body even more, Leo could see a firm-but-flexible, golden plate running across his front beneath his shirt. This… this was not normal. Leo was now truly and utterly afraid.

"What the heck are ya!?" the other boy shouted, and Leo nearly jumped out of his ivy skin. If the water was what had caused this, then…

He peered closer at the other boy, alarmed curiosity nipping at his mind. Now that he was in the light, Leo could see that the other's skin was a deep emerald, with the same features Leo noted on himself. Three fingers, tan plates, and a-

-_ shell._

"What are _we_?" Leo whispered in horror. The other boy looked down at himself fearfully, flinching in fear and hugging his chest when he saw that he too was no longer… human.

"What the heck happened to us!? We're… we're…"

"_Turtles_."

* * *

"Incredible!" Donnie said in awe, raising an olive arm to inspect the muscles that rippled beneath the skin. He had no idea what happened to make him, well, _mutate_ like this. In fact, he hadn't even realized that he had changed until he pulled himself from the sewer water onto a jutting pipe thick enough to rest comfortably on.

"Strangely numb," Don muttered to himself, poking and prodding at his new body, "but amazing! Unless this isn't my body…" He tapped a finger against his front teeth, seeking out that tooth gap that he was always so embarrassed about. He used to get teased about it endlessly in middle school, and since then he had carefully hidden his toothy smiles to avoid further embarrassment.

He still had it in this form, apparently, which made him relieved and self-conscious at the same time. So he didn't somehow switch bodies with another creature, but instead his body was transmuted into a terrapin-humanoid. Donnie let out a quiet laugh, wondering if he was dreaming. Dreams could be vivid, but Donnie doubted they could this accurate. Plus, he had already pulled the pinch test, and even with his muted senses he had let out a whimper of pain.

The scientist in Donnie was itching to break through and rattle off numerous theories and tests, and he probably would have launched into a rant with himself if he didn't at least have some of his sanity.

_Right now_, he thought logically_, I need to find Leo, Mikey and that other guy, see if they changed, too. I can move on from there, find out if this is linked with that earthquake, or something else entirely._

He slid off of the pipeline into the knee-deep water, glad that it didn't look too putrid. This area was probably reserved for the storm drains. If he kept moving, there should be an exit somewhere ahead. He just hoped that the others weren't in any kind of trouble.

_But then again_, Donnie thought as he looked at the traces of a glowing green substance floating downstream. _Maybe I should first find the source_.

So upstream it was.

* * *

"What tha heck happened to us?" Leo's companion asked, his voice not yet rid of his panic. For a guy who had been so confident and arrogant just two hours ago, according to Leo's still-living wristwatch, he sure could revert to a frightened child pretty quickly. "Please tell me we ain't gonna stay like this, man!"

"I don't know, okay." Leo sighed, exasperated as they walked down the sewer halls. This wasn't the first complaint the other made, and Leo could only wish it was the last. He couldn't focus on his fears at the same time he was trying to find a way out.

"Look, let's just keep moving. The sooner we get out of here, the better off I'll feel." _And the further away I'll be from you_, he mentally added.

The other growled, grabbing Leo's shoulder. He was almost able to stifle his surprised expression at the different anatomy this time. Almost.

"And then what? We walk the streets of New York an' just _hope _that we'll change back like some pretty _fairy tale_? Oh, no, Fearless, it ain't that simple!"

Leo huffed, tugging his arm away. "Would you stop calling me that? My name is Leo." He turned to face him, crossing his arms over his… chest? Plastron? Breastplate? "And I don't suppose that after all that happened that you would be interested in sharing your name? Or do you just want to be called 'hothead'?"

He snorted, balling his hands into fists. "Fine, _Leo_," he spat. "call me whatever tha' heck you want! As soon as I'm back ta normal, I don't hafta look at yer ugly mug anymore, and I'll be just another memory." He faltered a moment, confident mask slipping a little. "But… we don't have any idea how to reverse this, do we?"

Leo's expression softened at his downbeat realization. The other boy invisibly shook off his depression, snarling as he pushed past Leonardo.

"Jus' call me Raph, then. But don't think for a second that we're gonna be best buddies, or I'll crush your skull against the pavement!"

Leo smiled a little at that, walking in step behind him. "Raph, huh? That's an odd name…"

Raph growled in frustration. "It's short for Raphael, okay? Go ahead, make fun of me. I wanna see how well ya can function without a brain."

"No, no! It's cool!" Leo said, struggling to keep from laughing at Raph's defensiveness. "My name's short for Leonardo, after all."

"Deserve a medal for that, do ya?" They were walking side-by-side now, the walkway just wide enough for the both of them.

"No, just welcoming you into the fools-with-long-names club." Leo joked. He could see Raph was beginning to relax around him.

They turned into a side tunnel Leo pointed out and kept walking in silence. It felt like an hour had gone by before Raph spoke again.

"So… what are we gonna do about this?" He asked, gesturing towards their changed bodies with an unsure expression. Leo felt his look waver, and he faltered in his steps.

"Honestly… I don't know."

Raph looked hopefully at him. "But there's gotta be a way to reverse this, right? We can't stay like this forever… and I'm hungry. What if I can't eat what I normally do?"

"I'm sure we'll figure something out…" Leo said after a moment. "But if we can't-"

He was interrupted by a shrill shout echoing through the tunnels.

"Dudes, Bros… Anyone!? HELP!"

Leo broke into a run, trying to follow the yells. "That sounds like Mikey!" He gasped, putting on speed. To his relief, Raph was running beside him. Leo shot him a curious glance, and he shrugged.

"I ain't got anyone else to help me."

Leo nodded, turning to the left to follow the noises. He skidded to a stop, Raphael bumping into him and nearly sending him toppling. He had nearly run right off the edge of a platform into muddy water that seemed too far down to be safe. If he had fallen, it probably would've hurt like hitting concrete- if he would've even survived.

He scanned the area quickly, blue eyes spotting a squirming green spot clinging to a collapsing rusted ledge.

_Mikey_, Leo realized with a start. He had changed into a turtle too.

"Hold on!" he called over, backing up for a running start. If he was careful, he could just jump up next to him.

"Leo?" Mikey asked hopefully. "That you, dude?"

He broke into a sprint, kicking off the platform just as his toes met the edge. _Come on, come on_, Leo thought urgently. _Just let me make it!_

He landed on the ledge, quickly pulling Mikey to his feet just as a brace fell into the water. Only two beams were still supporting their weight, and they probably wouldn't last much longer. Leo turned to Mikey, looking into his wide blue eyes with urgency.

"Think you can hop over to that platform?" He asked, and Michelangelo nodded. "Then go!" Leo said, leaping across just as the last bolts came undone. Leo landed safely on the other side, but Mikey was not as fortunate.

He had jumped a moment too late, and his fingers just brushed the secure protrusion before he slipped, falling with a scream towards the filthy liquid below.

An emerald hand snapped out, snagging his wrist just before he tumbled out of reach. Looking down, Mikey saw the platform he had been standing on hit the water with an angry splash, and relief washed over him. He glanced up, smiling at his rescuer who was pulling him onto the ledge with a grunt of effort.

"I gotcha!" Raph said, hauling him up.

As soon as his feet were on the ground, Mikey shot up and pulled Raph into a tight hug, smiling widely.

"Dude… you saved me!" He squeezed just a little too tightly, and Raph nearly choked, struggling out of his firm grip.

"Alright, alright, I get it kid! Sheesh!" He grumbled, though Leo could see a ghost of a smile on his face.

"You…" Mikey sniffed, grinning up at him with watery blue eyes. "You're my hero!" He reached into the pocket of his sweat pants, yanking out a soggy wad of colorful paper. "I want you to have this back, as a reward!" He handed the paper to Raph, who took it with a look of confusion.

"This is…" His eyes lit up with a fury, and Leo stepped backwards fearfully. "You little rat! I knew you stole my comic book!" He grabbed Mikey by his hoodie front, practically on fire with rage. Mikey didn't seem to get that he should be scared for his life.

"Hey, man, it's still in mint-er, near-mint condition!"

"So that's what you stole!" Leo said, fixing Mikey with a disappointed stare. "And I stood up for you!"

Mikey snickered, dancing out of Raph's grip. "Hey I gave it back, didn't I? And besides, I don't need comic books anymore! Look at me now! I can _be_ a superhero! Just call me, uh… _Turtle Titan_!"

Leo held Raph back from charging at Mikey and shot him a look. "Mikey, we don't even know if we'll stay like this or not. Right now, we need to find a way out."

"Aww…" Mikey groaned, deflating a little. "Leo, you're no fun…"

"Now's not the time for fun," Leo scolded as he turned back into the tunnel they came out of. "We need to find Donnie. If the three of us got mixed into this, chances are that Donnie is too."

"How do we know Don hasn't already found his way out yet?" Raph asked, glaring at Mikey over Leo's shoulder.

"'Cause Don-Don's probably trying to figure out how we changed." Mikey answered as he skipped alongside Leo. Leo and Raph halted, looking at the freckled with a look of startled realization. They shared a look, and Mikey paused, wondering if he said something wrong.

"Uh, Mikey," Leo asked curiously. "Why would Donnie be looking for what changed us? Wouldn't he be more focused with, I don't know, getting out?"

Mikey shifted innocently. "Donnie liked using big words, and he was all mister-smart-guy, so I just figured… Did I say something wrong?"

"Actually, you might be right on th' mark with that one." Raph said, stunned, and Mikey beamed. "But don't think that 'cause you can come up with a good idea means yer off the hook for ruining my comic book!"

"Didn't think so, bro."

Leo paused, inspecting the water the tunnels were transporting. They stood back in what Leo assumed was the central pipeline, where he and Raph had been following upstream. "We floated downstream, right? That means we fell in the water further up…"

"So Donnie's headed there, too."

Leo nodded. "Let's go."

* * *

Honestly, Leo was amazed Raph and Mikey didn't harass one another in more than just insults. Raph seemed to get that Mikey was just goofing off, and his habit of smacking the smaller turtle became more of a teasing action than a spiteful one. Of course, Leo still had to step in when one got too harsh for the other.

They had been walking for almost twenty minutes when Leo began to notice the difference in the water. Thin, flimsy strands of iridescent aqua flicked through the stream, and the further they went the more there was. Leo suddenly stopped at the entrance to another pipeline. This was where that glowing stuff was coming from, and judging by how thick it was here, the source was just through that tunnel.

Leo looked over his shoulder. "Stay on the pathway guys. If this is the gunk that turned us green, who knows what more of it would do to us."

They nodded, although Leo didn't trust that glimmer of mischievousness in Mikey's eyes.

It was really a short tunnel, but what was at the end of it made Leo gape in shock.

"Whoooaahhh…"

They stepped out onto an island of spongy moss, incredibly soft and bouncy beneath their feet. A turquoise tree grew in the middle of the space, shedding shimmery leaves into a little lake of aqua-black liquid. Up above, where the ceiling would have been, was a crumbled hole that looked like it led into a subway station.

"So that's where we fell…" Leo muttered.

"Hey, guys!"

The trio turned when they were met with Donnie's voice, and they saw him running out from behind the odd tree. He fell victim to the transformation, too, it seemed. He still had his lanky height, but Leo could see flecks of red in his brown eyes that didn't exist before. He stopped before the group, studying them with a scientist's gaze, and Leo saw a gap between his two front teeth that he hadn't noticed until now.

"Fascinating…" the olive turtle mumbled. "I thought I couldn't be the only one affected, but the fact that our changes are so… so _similar_, it's astounding in and of itself! The chances of this happening are probably, like-"

"Will you shut up?" Raph grunted, obviously not liking being looked at as though under a microscope.

"Be nice, Raph." Leo chided. He turned back to Donatello. "I'm guessing you figured out what this stuff is?"

He shook his head, eyes glazed over as he ran equations and possibilities through his mind. "Not even close. All I've figured out is that that's the stuff that changed us. I think it's some sort of mutagenic fluid, but it doesn't even look like it's composed of earthly elements! It's almost like it's alien!"

Mikey perked up. "Alien!? Cool! Like, are we talking about slimy monsters with robot bodies and laser guns that are here to take over the earth and have converted us to make us weapons or-"

"Not that kind of alien!" Donnie interrupted. "What I mean is, it could be some form of bonding agent to combine genetic building blocks into a new hybrid species. It may have come from _alien origins_, outer space, even, but I seriously doubt it has anything to do with actual aliens."

Mikey looked dazed, and Leo guessed he was still stuck on "bonding agent". "Jeez, Donnie, didja kill off his few brain cells or something?" Raph asked, poking Mikey in the head.

"Huh? Oh, he'll be fine," Donnie said absently, scratching his head. "I'm just wondering how we discovered this and no one else has. I mean, wouldn't someone else have found this pool sooner? Things just aren't adding up…"

"Perhaps that is because it is not meant to make sense, but to defy it."

The four boys turned in surprise to see a figure step through the pipeline, tall and imposing. It wore a maroon robe that dusted against the little island's grass, and a tail swept out behind it. They gaped up at the biggest and most humanoid rodent they had ever seen.

"Perhaps an explanation would ease your minds. My name is Splinter."

* * *

**(Dun dun duuuunnn!)**


End file.
